charmhelpers.core.host

ChecksumError
add_group Add a group to the system
add_user_to_group Add a user to a group
adduser Add a user to the system
chdir
check_hash Validate a file using a cryptographic checksum.
chownr
cmp_pkgrevno Compare supplied revno with the revno of the installed package
cpu_arch
file_hash Generate a hash checksum of the contents of ‘path’ or None if not found.
fstab_add Adds the given device entry to the /etc/fstab file
fstab_remove Remove the given mountpoint entry from /etc/fstab
get_nic_hwaddr
get_nic_mtu
lchownr
list_nics Return a list of nics of given type(s)
lsb_release Return /etc/lsb-release in a dict
mkdir Create a directory
mount Mount a filesystem at a particular mountpoint
mounts Get a list of all mounted volumes as [[mountpoint,device],[...]]
pwgen Generate a random pasword.
restart_on_change Restart services based on configuration files changing
rsync Replicate the contents of a path
service Control a system service
service_available Determine whether a system service is available
service_reload Reload a system service, optionally falling back to restart if
service_restart Restart a system service
service_running Determine whether a system service is running
service_start Start a system service
service_stop Stop a system service
set_nic_mtu Set MTU on a network interface
symlink Create a symbolic link
umount Unmount a filesystem
write_file Create or overwrite a file with the contents of a byte string.

Tools for working with the host system

exception charmhelpers.core.host.ChecksumError

Bases: exceptions.ValueError

charmhelpers.core.host.add_group(group_name, system_group=False)

Add a group to the system

charmhelpers.core.host.add_user_to_group(username, group)

Add a user to a group

charmhelpers.core.host.adduser(username, password=None, shell='/bin/bash', system_user=False, group=None, groups=None)

Add a user to the system

charmhelpers.core.host.chdir(*args, **kwds)
charmhelpers.core.host.check_hash(path, checksum, hash_type='md5')

Validate a file using a cryptographic checksum.

Parameters:
  • checksum (str) – Value of the checksum used to validate the file.
  • hash_type (str) – Hash algorithm used to generate checksum. Can be any hash alrgorithm supported by hashlib, such as md5, sha1, sha256, sha512, etc.
Raises ChecksumError:
 

If the file fails the checksum
charmhelpers.core.host.chownr(path, owner, group, follow_links=True)
charmhelpers.core.host.cmp_pkgrevno(package, revno, pkgcache=None)

Compare supplied revno with the revno of the installed package

  • 1 => Installed revno is greater than supplied arg
  • 0 => Installed revno is the same as supplied arg
  • -1 => Installed revno is less than supplied arg

This function imports apt_cache function from charmhelpers.fetch if the pkgcache argument is None. Be sure to add charmhelpers.fetch if you call this function, or pass an apt_pkg.Cache() instance.

charmhelpers.core.host.cpu_arch()
charmhelpers.core.host.file_hash(path, hash_type='md5')

Generate a hash checksum of the contents of ‘path’ or None if not found.

Parameters:hash_type (str) – Any hash alrgorithm supported by hashlib, such as md5, sha1, sha256, sha512, etc.
charmhelpers.core.host.fstab_add(dev, mp, fs, options=None)

Adds the given device entry to the /etc/fstab file

charmhelpers.core.host.fstab_remove(mp)

Remove the given mountpoint entry from /etc/fstab

charmhelpers.core.host.get_nic_hwaddr(nic)
charmhelpers.core.host.get_nic_mtu(nic)
charmhelpers.core.host.lchownr(path, owner, group)
charmhelpers.core.host.list_nics(nic_type)

Return a list of nics of given type(s)

charmhelpers.core.host.lsb_release()

Return /etc/lsb-release in a dict

charmhelpers.core.host.mkdir(path, owner='root', group='root', perms=365, force=False)

Create a directory

charmhelpers.core.host.mount(device, mountpoint, options=None, persist=False, filesystem='ext3')

Mount a filesystem at a particular mountpoint

charmhelpers.core.host.mounts()

Get a list of all mounted volumes as [[mountpoint,device],[...]]

charmhelpers.core.host.pwgen(length=None)

Generate a random pasword.

charmhelpers.core.host.restart_on_change(restart_map, stopstart=False)

Restart services based on configuration files changing

This function is used a decorator, for example:

@restart_on_change({
    '/etc/ceph/ceph.conf': [ 'cinder-api', 'cinder-volume' ]
    })
def ceph_client_changed():
    pass  # your code here

In this example, the cinder-api and cinder-volume services would be restarted if /etc/ceph/ceph.conf is changed by the ceph_client_changed function.

charmhelpers.core.host.rsync(from_path, to_path, flags='-r', options=None)

Replicate the contents of a path

charmhelpers.core.host.service(action, service_name)

Control a system service

charmhelpers.core.host.service_available(service_name)

Determine whether a system service is available

charmhelpers.core.host.service_reload(service_name, restart_on_failure=False)

Reload a system service, optionally falling back to restart if reload fails

charmhelpers.core.host.service_restart(service_name)

Restart a system service

charmhelpers.core.host.service_running(service)

Determine whether a system service is running

charmhelpers.core.host.service_start(service_name)

Start a system service

charmhelpers.core.host.service_stop(service_name)

Stop a system service

charmhelpers.core.host.set_nic_mtu(nic, mtu)

Set MTU on a network interface

Create a symbolic link

charmhelpers.core.host.umount(mountpoint, persist=False)

Unmount a filesystem

charmhelpers.core.host.write_file(path, content, owner='root', group='root', perms=292)

Create or overwrite a file with the contents of a byte string.